Merge Compositor's ScrollbarAnimationControllers into single class

cc/input/single_scrollbar_animation_controller_thinning.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/input/single_scrollbar_animation_controller_thinning.h"
 
 #include <algorithm>
 
 #include "base/memory/ptr_util.h"
 #include "base/time/time.h"
 #include "cc/input/scrollbar_animation_controller.h"
 #include "cc/layers/layer_impl.h"
 #include "cc/layers/scrollbar_layer_impl_base.h"
 #include "cc/trees/layer_tree_impl.h"
 
-namespace {
-const float kIdleThicknessScale = 0.4f;
-const float kDefaultMouseMoveDistanceToTriggerAnimation = 25.f;
-}
-
 namespace cc {
 
 std::unique_ptr<SingleScrollbarAnimationControllerThinning>
 SingleScrollbarAnimationControllerThinning::Create(
     int scroll_layer_id,
     ScrollbarOrientation orientation,
     ScrollbarAnimationControllerClient* client,
     base::TimeDelta thinning_duration) {
   return base::WrapUnique(new SingleScrollbarAnimationControllerThinning(
       scroll_layer_id, orientation, client, thinning_duration));
 }
 
 SingleScrollbarAnimationControllerThinning::
     SingleScrollbarAnimationControllerThinning(
         int scroll_layer_id,
         ScrollbarOrientation orientation,
         ScrollbarAnimationControllerClient* client,
         base::TimeDelta thinning_duration)
     : client_(client),
       is_animating_(false),
       scroll_layer_id_(scroll_layer_id),
       orientation_(orientation),
       captured_(false),
       mouse_is_over_scrollbar_(false),
       mouse_is_near_scrollbar_(false),
       thickness_change_(NONE),
-      mouse_move_distance_to_trigger_animation_(
-          kDefaultMouseMoveDistanceToTriggerAnimation),
       thinning_duration_(thinning_duration) {
   ApplyThumbThicknessScale(kIdleThicknessScale);
 }
 
 bool SingleScrollbarAnimationControllerThinning::Animate(base::TimeTicks now) {
   if (!is_animating_)
     return false;
 
   if (last_awaken_time_.is_null())
     last_awaken_time_ = now;
@@ skipping 74 matching lines @@
     return;
 
   thickness_change_ = DECREASE;
   StartAnimation();
 }
 
 void SingleScrollbarAnimationControllerThinning::DidMouseMoveNear(
     float distance) {
   bool mouse_is_over_scrollbar = distance == 0.0f;
   bool mouse_is_near_scrollbar =
-      distance < mouse_move_distance_to_trigger_animation_;
+      distance < kDefaultMouseMoveDistanceToTriggerAnimation;
 
   if (!captured_ && mouse_is_near_scrollbar != mouse_is_near_scrollbar_) {
     thickness_change_ = mouse_is_near_scrollbar ? INCREASE : DECREASE;
     StartAnimation();
   }
   mouse_is_near_scrollbar_ = mouse_is_near_scrollbar;
   mouse_is_over_scrollbar_ = mouse_is_over_scrollbar;
 }
 
 float SingleScrollbarAnimationControllerThinning::ThumbThicknessScaleAt(
@@ skipping 41 matching lines @@
 
     float scale = AdjustScale(thumb_thickness_scale,
                               scrollbar->thumb_thickness_scale_factor(),
                               thickness_change_, kIdleThicknessScale, 1);
 
     scrollbar->SetThumbThicknessScaleFactor(scale);
   }
 }
 
 }  // namespace cc